SWEET-POTATO 445 



418. Propagatibn by the use of vine cuttings. — When 

 the bedded potatoes do not furnish enough slips for the 

 desired area, they may be supplemented by setting out in 

 June or early July sections of about 18 inches of vine cut 

 from the early plants. Vine cuttings are usually set out 

 just after a rain by a stick or lath with concave base, 

 pressed down on the center of the vine (Fig. 192). 



Roots produced by vine cuttings are preferred for 

 bedding. This is because such potatoes usually escape 

 black rot, a disease which, if present in the bed, is con- 

 veyed to the shps by the diseased potatoes. The prefer- 

 ence for potatoes from vine cuttings (Fig. 194) may also 

 be due to their greater soundness, sometimes attributable 

 to the late date of planting. 



419. Distance between plants. — In the cotton states, 

 the rows are usually about 3^ feet apart. Truckers 

 sometimes plant in narrower rows. In several experi- 

 ments, a distance of 18 inches between plants afforded 

 larger yields than were obtained either by closer or wider 

 spacing. 



420. Preparation of land. — It too frequently happens 

 that the land is merely thrown into beds without any pre- 

 vious plowing. For this crop, which makes a large yield 

 per acre and requires a soft, mellow soil for the easy trans- 

 planting of the slips and for the full development of the 

 crop, it is profitable to give thorough preparation. This 

 should consist of broadcast plowing, repeated harrowing, 

 and the formation of beds, which are usually thrown up 

 over a furrow in which fertihzer has been apphed. Before 

 bedding and after the fertihzer is drilled in, the latter 

 should be thoroughly incorporated with the soil by running 



